The invention relates to a branch shears tool or the like in particular, having two blades that are movable in relation to each other, of which one blade is rigidly connected with a housing and the other blade can be moved by an electric motor arranged in the housing via a threaded spindle capable of being rotated by said electric motor, a threaded nut located on the threaded spindle and supported so as to be non-rotating and a rod assembly connected to the threaded nut.
EP 0 291 431-A1 discloses branch shears of this class. In this case, the translational motions of the spindle nut are limited by an electrical or electronic stopping device that directly or indirectly acts on the electric motor. In addition, the actuating mechanism is fixedly connected with the threaded spindle and consequently follows its feed motions so that the actuating mechanism assumes different operating positions. The electrical control arrangement also has a movable magnetic control rod which is acted upon by the actuating mechanism as well as a fixedly attached sensor in the vicinity of the magnetic control rod. Aside from the considerable constructional expense required by this embodiment, the changing positions of the actuating mechanism do not allow easy handling.
In addition, EP 0 118 350-A1 discloses garden shears in which the movable blade has a drive connection with a disk arranged on the shaft driven by the drive motor. In order to switch off the electric motor with the cutting blades in open position, the disk is provided with an operating cam; in addition, a double-throw switch is installed in the housing, the switch being actuated by the pivotable blade so that a reverse rotation of the electric motor is immediately initiated when the shears are closed. Thus the blades are unable to assume any intermediate positions, but rather the blades are closed by the force of the drive motor and opened by the force of a spring. Also, the force of the return spring must always be overcome during a cutting operation and it must be tensioned; the drive motor must therefore be provided with sufficient power. Aside from the fact that the return spring is a part subject to wear and can break, its force is occasionally not sufficient to open the shears, particularly when relatively thick branches are to be cut. Thus the actuating and transferring mechanisms provided in these shears do not permit optimal handling.